18221764 has 12 divisors (see below), whose sum is σ = 34787088. Its totient is φ = 8282600.

The previous prime is 18221761. The next prime is 18221783. The reversal of 18221764 is 46712281.

It is not an unprimeable number, because it can be changed into a prime (18221761) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 207022 + ... + 207109.

It is an arithmetic number, because the mean of its divisors is an integer number (2898924).

Almost surely, 2^18221764 is an apocalyptic number.

It is an amenable number.

18221764 is a deficient number, since it is larger than the sum of its proper divisors (16565324).

18221764 is a wasteful number, since it uses less digits than its factorization.

18221764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 414146 (or 414144 counting only the distinct ones).

The product of its digits is 5376, while the sum is 31.

The square root of 18221764 is about 4268.6958195683. The cubic root of 18221764 is about 263.1460200087.

It can be divided in two parts, 182217 and 64, that added together give a palindrome (182281).

The spelling of 18221764 in words is "eighteen million, two hundred twenty-one thousand, seven hundred sixty-four".